Preheat the oven to 200°C/Gas Mark 6. Butter four individual (150ml (¼pt) ramekin dishes, then divide the fruit between the dishes.
Whisk the egg whites until firm, then whisk in half the sugar, followed by the rest of the sugar until stiff and glossy. Quickly whisk in the jam, then spoon the meringue into the dishes. Put the ramekins into a small roasting tin and bake for 12-15 minutes, until well risen.
Dust generously with icing sugar and serve immediately. If you like, serve with a scoop of vanilla ice cream.